I always did, but now with a gauge I don't bother. I just like to see it below that middle line.
Each line represents 4.166667 degrees.
The middle of 160-210 is 185.
You have 5 lines but you have 6 gaps between
160-185, therefore its not 5 degrees its 4.167
But if you have this gauge then it is 5 degrees up to 100*c: